Machines which grind the surface of a roll to within very close dimensional tolerances are generally known as roll grinding machines. These machines are capable of defining particular contours such as the well-known crown contour along the length of the roll. To achieve these ends, roll grinding machines employ sophisticated mechanisms which position the grinding tool relative to the workpiece roll. These mechanisms include an infeed device which moves the grinding wheel toward the workpiece until a predefined grinding depth has been reached.
The systems employed in the past to move the grinding wheel have usually consisted of complex mechanical arrangements. The complexity of these mechanical arrangements has often been attributable to the number of different types of infeed that may be necessary during a roll grinding operation. For instance, the mechanical infeed arrangements may be called upon to implement several different types of infeed either simultaneously or selectively while proceeding along the length of the workpiece. These types of infeed may be required in conjunction with the overall grinding profile that is to be accomplished. This has necessarily led to rather complex mechanical arrangements that are capable of responding to all these various possibilities. This has in turn often led to the deployment of a number of different motors to perform specified types of infeed. The motors are usually accommodated within the mechanical arrangements in such a manner so as to compound or superimpose their separate drive functions. The motors also had their separate and individual controls associated therewith. These controls have usually been only responsive to one or two different types of infeed commands. The separately dedicated control systems have for the most part not been inter-related. In other words, there has heretofore not been a single motor control system which has been capable of implementing all types of infeed commands which may be necessary in a roll grinding application.
A single motor control system has been disclosed in U.S. patent application Ser. No. 108,338, entitled "Control Apparatus for Roll Grinders", dated Dec. 31, 1979, and now U.S. Pat. No. 4,371,941, dated Feb. 1, 1953. This control system includes a digital command circuit which responds to forward and reverse digital commands coming from a number of different sources. The digital command output circuit in turn generates forward and reverse pulses to a single motor which moves the grinding wheel inwardly or outwardly relative to a workpiece. These generated pulses may occur in such a manner as to cause abrupt reversals in the motor. It has been found that this occurs in a mode of operation wherein wheel wear compensation is being effected during the grinding of a profile on the workpiece.